Method of manufacturing uniformly-loaded conductors used for signaling purposes



June 12, 1928. r 1,673,208

E. SCHURER METHOD OF MANUFACTURING UNIFORMLY LOADED CONDUCTORS USED FOR A SIGNALING PURPOSES Filed Aug. 13, 1925 Patented June 12, 1928.

UNITED STATES PATENT OFFICE.

SCH'U'RER, OF COLOGNE-MULHEIM. GERMANY, AS SIGNOR TO FELTEN AND GUILLEAUME CARLSWERK ACTIEN GESELLSCHAFT, F COLOGNE-MULHEIM,-

GERMANY.

METHOD or MANUFACTURING UNIFOBMLY-LOADED CONDUCTORS USED non SIGNAL- me PURPOSES.

Application filed August 13, 1925, Serial No. 50,145, and in Germany December 18, 1924.

This invention relates to a. method of manufacturing uniformly loaded conductors.

It has been proposed to interpose a thin layer of material containing carbon, such as for example paper, when winding the loading strip on to the actual conductor. By this means when the conductor is annealed, the burning of the layer causes sufiicient space to be left for the copper to expand, thus avoiding tension in the loading strip. This .method has the disadvantage that the magnetizable materials may absorb carbon. If this drawback is avoided by sub- 7 stituting a layer of inorganic substance for that containing carbon, the material forming the layer combines with the copperor the magnetizable substance thus affecting the mechanical and electrical properties of the conductor.

It has been proposed in atent application Serial Number 50,144, file August 13, 1925, to coat the actual conductor of signaling lines loaded uniformly with a highly permeable material, before the latter is applied, with a 2 layer of lac, the latter being removed by a solvent after the loading material has been wound on the conductor, for the purpose of avoiding the undesirable tension in the loading ,material which otherwise occurs owing to the copper expanding to a greater extent. As a matterof fact when this method is employed, a very highly permeable loading material is obtained.

On the other hand it is a very lengthy and diflicult operation to apply the lac in a sufliciently uniform layer to the conductor.

The object of the present invention is to provide an improved method which obviates this drawback. According to the invention, instead of coating the actual conductor with one of the lacs containing celluloid fproposed in the patent application above re erred to, 7 a stri made of cellulose ester or cellulose ether is wound tightly around the conductor and after the loading material is placed thereon, this strip is dissolved by placing the conductor in a suitable solvent such as for v instance amyl acetate, acetone and the like. The conductor is then annealed in a known manner. The invention will be better under- Stood by reference to the accompanying drawings, in which Figure 1 illustrates a conductor around which the soluble strip is Wound, and Figure 2 shows the same conductor after the said strip has been dissolved. In these figures a is the copper conductor, 2)

the strip of cellulose ester, cellulose ether or solving without using heat.

According to a further feature of the invention, use is made of paper as intermediary layer in place of the expensive celluloid-like substances and the paper is dissolved out by cupric oxide ammonia or a similar solvent in an atmosphere free from oxygen. v

Finally the invention is not limited to the use of the substances referred to as intermediary layers, but any material which can be obtained in the form of a strip may be employed for this purpose, provided it is soluble in a liquid which does not affect either the copper or the loading material.

-What I claim is 1. A method of manufacturing uniformly loaded conductors used for signaling purposes, consisting in tightly winding round the'conductor a strip made of a substance which is soluble in a liquid which does not attack either copper or the loading material, surrounding the conductor with the loading material, placing it into a liquid which dis-v solvesthe strip and finally annealing the conductor and loading material.

2. A method of manufacturing uniformly loaded conductors used for signaling purposes, consisting in tightly winding round the conductor a strip made of paper, surpaper strip, and finally annealing the conmaterial, placing it in cupric oxide ammonia ductor and loadlng material. to dissolve the paper strip, and finally an- 3. A method of manufactur ng uniformly nealing the conductor and loading material. 10 loaded conductors used for signaling pur- In testimony whereof I have signed my 5 poses, consisting in tightly Winding round name to this specification.

the conductor a strip made of aper, surrounding the conductor with t e loading EUGEN S CHURER. 

